Method of preparing sulpho-carboxylic ester salts



Patented Jan. 2, 1940 PATENT OFFICE METHOD OF PREPARING SULPHO-GAR-BOXYLIC ESTER SALTS Frank J.

111., assignors to The Calm and Morris Bl Katzman, Chicago,

Emulsol Corporation, Chicago, 111., a corporation of Illinois NoDrawing.

9 Claims.

This invention is concerned with the preparation of novel chemicalcompounds and relates particularly to the preparation of compoundshaving unusual eflicacy in various preparations,

particularly for use in hair washes, shampoos and the like.

v Compounds falling into the category of sulphocarboxylic esters ofhigher molecular weight alco-' hols and of derivatives of polyhydroxysubstances 10 are already known and have been disclosed in variouspublications and patents among which may be cited United States PatentsNos. 1,917,250"

and 1,917,255 and British Patent No. 377,249.

These compounds are generally prepared and em-' ployed in the form oftheir alkali metal or ammonium salts, as the patents cited above show.

It has been found that compounds of the char-.

acter indicated, particularly the sulpho-acetates of the straight chainhigher aliphatic alcohols, 94) such as lauryl sulpho-acetate, myristylsulphoacetate, and the like, in the form of their alkali metal salts,for example, the potassium salt, possess some utility in the preparationof hair washes, shampoos and the I like." However, a 16 seriousdisadvantage of such alkali metal salts,

and this is'even more true of the free acid derivatives, is theirrelatively poor solubility in cold water.

It has been found that when the siilpho-car- -& boxylic esters areneutralized with organic nitrogeneous bases as, for example,alkylolamines such as mono-, diand tri-ethanolamine .or mixtures thereofsuch as are present in commercial triethanolamine, compounds resultwhich have 86 greatly enhanced solubility in cold water thereby Yrendering the compounds admirably suited to the preparation of hairwashes, shampoos and the like. In further investigating this matter,possible methods of preparing the desired compounds 40 were consideredand, as a result of careful study and research, novel methods wereevolved for preparing the compounds in a relatively simple andinexpensive manner.

It is accordingly one object of the present invention to preparesulpho-carbcxylic esters neutralized with organic nitrogenous bases tomarkedly increase the water-soluble characteristics of said esters.

Another object is to prepare alkylolamine'sa'lts W of sulpho-carboxylicesters.

. Still another object of the invention is the preparation of ,hairwashes, shampoos and the like containing sulpho-jc'arboxylic estersneutralized with organic nitrogenous bases.

ll Afurther and important object of the invention Application September29, 1937, Serial No. 166,388

is a novel method of preparing the chemical compounds referred tohereiiiabove.

Other features will become even more apparent in the light of thefollowing detailed description of the invention.

In the preparation of alkali metal sulpho-car boxylic esters such assulpho-acetates, it is mown, as shown, for example, by the patentsreferred to hereinabove, to employ a method'involving initially reactinga higher molecular weight alcohol, such as lauryl alcohol, withchloracetic or bromacetic acid or the like to produce the chloracetic orbromacetic acid ester of lauryl alcohol in accordance with the followingequation: (1) o,,Hog+c1co-omc 1 i1 2s CC HCl+l0l 4'. The resultingproduct, preferably washed free of the formed hydrochloric acid and theunreacte'd chloracetic acid, is then treated with an aqueous solution ofan alkali metal sulphite, such as KzSOs, in accordance with theso-called Strecker reaction to produce the alkali metal sulphoacetate asindicated in the following equation:

The Strecker reaction appears to operate best 1 when potassium sulphiteis employed. Sodium sulphite operates well while ammonium sulphite isnot quite so satisfactory as sodium sulphite.

In the course of the investigational work in connection with the presentinvention, various methods were evolved and employed in an endeavor toproduce alkylolamine and similar salts of sulpho-carboxylic esters butwithout success. 40 It was finally discovered, however, that highly,advantageous results could be achieved by reacting an alkali metal orsimilar salt of a sulphocarboxylic ester, such as lauryl potassiumsulphoacetate, with an organic nitrogenous base such- .asmonoethanolamine, and with a compound which would react with thecationic constituent of the sulpho-acetate salt to produce a compoundmore insoluble'than the sulpho-acetate salt whereby the more insolublecompound would precipitate out and could be removed by filtration or thelike, leaving the monoethanolamine salt of the sulphoacetate in solutionfrom which it could, if desired, be recovered by evaporation or dryingof the solution.

The reaction takes place when the alkali metal or similar salt of thesulpho-carboxylic acid ester is more soluble or less insoluble than thesalt or the like such as potassium acidtartrate which forms during thereaction. Thus, in the specific .exampl'e referred to above, laurylpotassium sulpho-acetate being more'soluble or less insoluble thanpotassium acid tartrate, the reaction takes place. On the other hand,this particular reac-. tion does not appear to take place when stearylpotassium sulpho-acetate is substituted for lauryl potassiumsulpho-acetate, presumably because stearyl potassium sulpho-acetate isless soluble than potassium acid tartrate.

In order to enable those skilled in the art to understand the nature ofthe invention even more fully, the following examples are given by wayof illustration. It will be understood, however, that the specificreactants, the proportions thereof, and the times and temperatures maybe varied within limits without departing from the spirit of theinvention. The examples, therefore, are to be taken in an illustrativerather than in a limitative sense, the full scope of the invention beingpointed out in the claims.

Example I A. 200 grams of crystalline lauryl potassium sulpho-acetate,prepared from commercial lauryl alcohol, were dissolved in 400 cc. ofwater at 80 degrees C. to produce a relatively stifi paste.

B. 150 grams of tartaric acid and 141 grams of triethanolamine weredissolved in 400 cc. of water.

, C. Compositions A' and B were then stirred together at a temperatureof about 90 degrees C. A heavy precipitate came down and the previouslyviscous mixture became quite mobile.- The precipitate, which comprisespotassium acid tartrate, was filtered OE and the filtrate was thenneutralized with 50 grams of triethanolamine. The final solution wasquite viscous, containing in the neighborhood of 20% of lauryltriethanolamine sulpho-acetate. It possessed unusually good foamingcharacteristics andmade an excellent shampoo.

Example II 133.5 grams of potassium lauryl sulpho-acetate(CnHuO-C-CHr-SQaK) 28.7 grams of monoethanolamine in 200 cc. of

water. These two solutions were mixed together at a temperature ofaboutdegrees C. and the resulting mixture thereof was allowed to cool toroom temperature. The liquid was then filtered from the precipitatedpotassium acid tartrate. The filtrate was a viscous, strongly foaming,substantially odorless and colorless liquid after having beenneutralized with 6.7 grams of monoethanolamine to a litmus bluereaction. The solution contained 13.8% of the monoethanolamine salt oflauryl sulpho-acetate and 2.9% of the tartrate of monoethanolamine.

The solution had excellent foaming properties and. formed an admirableshampoo.

Example III 133 grams of potassium lauryl sulpho-acetate were dissolvedin 700 cc. of boiling water and the resulting solution was then mixedwith a previously prepared solution containing 69 grams of tartaricacid, 36.6 grams of pyridine and 200 cc. of water. The two solutionswere mixed at a temperature of about 90 degrees C. and were then allowedto cool to room temperature whereupon the resulting solution wasfiltered from the potassium acid tartrate which had precipitated out.Approximately 780 cc. of a yellow colored limpid solution were'obtainedwhich had excellent foaming properties in hard water as well as in thepresence of alkalies and acids. The solution contained a substantialproportion of the pyridine salt of the sulpho-acetate of lauryl alcohol.a

1 Example IV 173' grams of lauryl potassium sulpho-acetate weredissolved in 1050 cc. of boiling water and mixed with a solutioncontaining 93 grams of tartaric acid, 51 grams of piperidine and 300 cc.of water. After cooling to approximately room temperature, the solutionwas filtered off from. .the precipitated potassium acid tartrate and thesolution was then neutralized to a methyl red yellow with 20 grams ofpiperidine. A waterwhite viscous liquid was obtained possessing strongfoaming properties in alkaline or acid aqueous media as well as in hardwater. The solution contained the piperidine salt of laurylsulpho-acetate and was very suitable for use as a shampoo.

Example V 453 grams of lauryl potassium sulpho-acetate, I

dissolved in 210 cc. of water.

The resulting. solution was, then allowedto' cool for about a day atroom temperature and was then decanted andfiltered from the precipitateof potassium acid. tartrate, the latter then being washed with 50 cc. ofwater and the wash water being added to the filtrate.

To the approximately 2,660 grams of solution thus obtained, about 20grams of monoethanolamine were added until methylred gave a yellowcolor-.1 There was then added to said solution cc. of a solution ofmonoethanolamine sulphate in order to thicken the solution so as toadding a solution of 325 grams of monoethanolamine dissolved in 250 cc.of water to a. solution of a stoichiometrically equivalent amount of 96%sulphuric acid dissolved in 580 cc. of water. I

Example VI An aqueous solution of 8.1 parts, by weight, of acidmethylpyridinium tartrate in 17 parts, by weight, ofwater was preparedby mixing one mol of 0.166 normal methylpyrldinium hydroxide solutionwith an aqueous solution of onemol of tartaric acid and evaporatingdown. This solution was then heated to a temperature of about 90 degreesC. and was then added: to a previously heated solution, also at about 90degrees 0., containing 10.4 parts, by weight, of

lauryl potassium sulpho-acetate' and 50 parts, by weight, of water. Themass was permitted to cool to approximately 25 degrees C. and the acidpotassium tartrate which had precipitated out was filtered off. Theresulting clear filtrate'was neutralized to yellow methylred with 20volume parts of 0.167 normal methyl-pyridinium hydroxide solution. Theresulting solution, containing a substantial proportion of themethylpyridininum salt of lauryl sulpho-acetate, was water-white,viscous, substantially odorless, and had excellent foaming properties inhard water as well as in aqueous acidulated media. It wasvery suitable'for use as a hair wash or shampoo.

Those skilled in the art will readily be able to carry out theinvention, make diverse variations all of which, however, are within thespirit of the invention in view of the detailed explanation and guidingprinciples set out hereinabove.

It will be appreciated, for example, that other organic nitrogenousbases may be employed in place of those described hereinabove.Illustrative of additional bases of this type are propanolamines,butanolamines, hexanolamines, glycerolamines, dibutyl ethanolamine,diethanol ethyl amine, cyclohexyl ethanolamine, alkylol polyamines suchas alk'ylol derivatives of ethylene diamine, quaternary ammonium basesor hydroxides such as tetra-methyl ammonium hydroxide, tetra-ethylammonium hydroxide, quaternary ammonium bases with dissimilar alkylradicals such as methyl-triethyl ammonium hydroxide, propyl-trimethylammonium hydroxide, and'the like.

Again, it is evident that pure or single sulphocarboxylic esters neednot be employed. Mixtures are, in many cases, at least equally.efiicacious as, for example, the sulpho-carboxylic esters prepared fromthe product known as Lorol Technical which comprises a mixture of fattyalcohols derived from the hydrogenation of coconut oil or the free fattyacids of coconut oil. Lauryl alcohol comprises about 60% of the totalalcohol mixture, the remaining alcohols running from C6 to C18.Similarly, it is apparent that mixtures of difierent organic nitrogenousbases, such as mixtures of those referredto hereinabove, may be employedwith eflicacious results. Indeed, in order to obtain varied solubilityand other characteristics mixturesof different organic nitrogenous basesmay be employed wit mixtures of different sulpho-carboxylic estersliInstead of employing tartaric acid as described above, oxalic acid andother acids such as perchloric acid or acids of organic character can beused whose alkali metal or other salts or acid salts are more insolublethan the salt of the sulpho-carboxylic acid employed as one of thereactants at the concentrations and under the As indicated in Example V,the solution of the organic nitrogenous base salt of thesulphocarboxylic ester may be thickened, if desired, by the additionthereto of monoethanolamine sulphate. In place of the latter, organicnitrogenous bases other than monoethanolamine, such as those disclosedabove, may be neutralized with acids other than sulphuric acid as, forexample, phosphoric acids, nitric acid, acetic acid and the like, andemployed for thickening purposes. In general, the thickening materialmay be a neutral water-soluble salt, the cation of which does notprecipitate out the sulphocarboxylic ester.

If it is desired to still further decrease the solubility of the salt,such as potassium acidtartrate, methyl alcohol, ethyl alcohol or otherorganic solvents may be added to the reaction mixture to provide anenvironment in which the potassium acid tartrate or the like is evenstill more insoluble than it is in cold water alone.

The term higher, as employed herein in connection with the alcoholsulpho-carboxylic esters, is intended to mean not less than eight carbonatoms and, concomitantly, the term lower will beunderstood to mean lessthan eight.

What we claim as new and desire to protect by Letters Patent of theUnited States is:

l. The method of preparing esters of alcohols containing at least 8carbon atoms and sulphocarboxylic acids containing less than 8 carbonatoms, the hydrogen of. the sulphonic groups of which is replaced by anorganic nitrogenous base, which includes the steps of reacting anorganic nitrogenous base, an ester of an alcohol containing at least 8carbon atoms and a sulpho-carboxylic acid containing less than 8 carbonatoms, the hydrogen of the sulphonic group of which is replaced'by ametal cation, an acid which reacts with the metal salt of thesulpho-carboxylic acid ester to produce a salt of said acid and themetal cation of said sulpho-carboxylic acid ester which is moreinsoluble than the sulpho-carboxylic acid ester metal salt constitutingone of the reactants whereby a precipitate is formed, and thenseparatingsaid precipitate from the solution.

2. The method of claim 1 wherein said metal cation is potassium.

3. The method of preparing sulpho-acetates of alcohols containing atleast eight carbon atoms, the hydrogen of the sulphonic group of whichis replaced by an-organic nitrogenous base, which comprises providing anaqueous material containing a substantial proportion of the potassiumsalt of a sulpho-acetate of an alcohol havingat least eight carbonatoms, adding an aqueous solution containing tartaric acid and anorganic nitrogenous base, stirring the mixture, and removing theresulting precipitate of potassium acid tartrate.

4. The method of preparing alkylolamine sulpho-acetates of aliphaticalcohols having at least eight carbon atoms which includes the steps ofreacting, in aqueous media, an aliphatic alcohol potassiumsulpho-acetate, the alcohol radical of which'con'ains at least eightcarbon atoms, an

is less water-soluble than the aliphatic alcohol potassium'sulpho-acetate whereby said salt is precipitated, and then separatingthe precipitate rating the resulting precipitate of potassium acidtartrate.

6. The method of preparing lauryl monoethanolamine sulpho-acetate whichcomprises providing an aqueous material containing a substantialproportion of lauryl potassium sulphoacetate, adding an aqueoussolution. containing tartaric acid and monoethanolamine, stirring themixture at a temperature of about 90 degrees C., and removing theresulting precipitate of potassium acid tartrate after cooling saidmixture.

' 7. The method of preparing lauryl alkylolamine sulpho-acetate whichincludes the steps of reacting; in aqueous media,- lauryl potassiumsulpho-acetate, tartaric acid, and alkylolamine and separating theresulting precipitate of potassium acid tartrate.

8. The method of preparing lauryl alkylolamine sulpho-acetate whichcomprises providingan aqueous material containing a substantialproportion of lauryl potassium sulpho-acetate, adding an aqueoussolution containing tartaric acid and alkylolamine, stirring the mixtureat a temperature of about 90 degrees C.,' and removing the resultingprecipitate of potassium acid tartrate after cooling said mixture.- a

9'. The method of preparing lauryl sulphoacetate the hydrogen of thesulphonicacid radical of which is replaced by an organic nitrogenousbase which includes the steps of reacting lauryl potassiumsulpho-acetate, tartaric acid, and an I organic nitrogenous base, andseparating, the resulting precipitate of potassium acid tartrate.

' FRANK J. camp MORRIS B. KATZMAN.

